• Facebook
712-433-0000 • Toll Free 877-474-SOIL
Soil Solutions LLC
  • About
  • Products
    • PRO CAL 40
    • NatureGro
    • Nutra Bio
    • NatureGro(C)
  • Services
    • Maximum Farming System
    • Field Application
  • Resources
    • Crop Response
      Case Studies
    • Reports & Links
    • From Our Desk
    • Newsletter
    • Blog
  • Contact
  • Menu Menu
You are here: Home1 / Blog2 / General3 / Yields Can be Affected by Relative Magnesium Levels
Printer Friendly Printer Friendly

Yields Can be Affected by Relative Magnesium Levels

February 19, 2019

As we analyze yield data from our clients each year it is interesting to see what soil test factors have the greatest impacts on yield.  This can vary from year to year, but we often see the influence of high magnesium on yields.  You can see below from both soybean and corn 2018 yield data from a customer’s field.  It is more prevalent in stress years, however, than in years when we have ideal growing conditions.  This specific customer had much above average moisture this year.

Soybean Yield vs. % Mg Soil Test

A 9 bushel difference between the optimum % Mg levels and the Highest % Mg levels across 900 acres. ($72/acre more revenue)

 

 

 

 

 

 

Corn Yield vs % Mg Soil Test

A 11 bushel difference between the optimum % Mg levels and the second highest % Mg levels across 1000 acres. ($40/acre more revenue) (%Mg > 30%  was 50 acre bushels less)

 

 

 

 

 

 

 

 

Why are yields affected by high magnesium levels in stress years?

Less Air in the Soil

Magnesium molecule attracts water molecules to a greater degree than calcium.  A magnesium molecule can have as high as 22 molecules of water around it.  The hydrated radius of magnesium is 400 times larger than its dehydrated radius.  There is a 25-fold difference between magnesium and calcium.

This affects soil environments and will affect the amount of air that is found in the soil.  If you have less air, you will have less microbial activity for organic matter decomposition and less mycorrhizae for nutrient uptake.  With less microbial activity nutrients aren’t as available as soon.  Less microbial activity will also decrease the amount of nitrogen fixation in legume crops such as soybeans and alfalfa.

Less air also means slower growth by roots.  This can also affect plant growth and nutrient uptake.

Colder Soils

If  the soil contains more water, the soil doesn’t warm up as fast in the spring.  Colder soils also affect microbial activity and early plant growth and nutrient availability.  Consequently, we prefer better placement of nutrients on these soils. Soybeans planted earlier in these soils will mean slower nodulation and less nitrogen fixation.

Poorer Root Growth

Magnesium also will weaken the stability of the soil aggregates (clay particle groupings).  This will mean soils will become dispersed more easily and lack a good soil structure. This can decrease root growth, especially fibrous roots.   As these soils dry, they will become hard and will crack open.  This causes roots to be torn and not able to take up water and nutrients from deeper depths during drought periods.  Some of the largest yield differences due to high magnesium soils, I have seen during drought periods.  In 2012 (drought year), I was notified by an extension agronomist that magnesium levels in the soil was the best correlation to yield differences.  The soils with the highest magnesium levels had the lowest yields.

Air and Water Management is Most Important to Yield!

It is interesting that so much emphasis is put on fertility levels and the influence they have on yield.  It is more common to see factors that affect air and water management have a greater affect on yield.  One tool that is effective in lowering % magnesium and improving air and water management in soils is gypsum.  Our observations show that we can lower the % magnesium by about 5% for each ton of gypsum we apply, and this greatly changes the soil condition and how the soils perform.  Our observations also show good yield responses especially in those more stressful years, either too wet or too dry.  Plus, as we plan to plant crops earlier, gypsum applications make the soils planter ready sooner (less sticky) allowing you to get in the fields when you aim to.  With less bound water and more air, the soil will actually warm up sooner.

As the data above shows, to reduce the affects of stressful years, it is best to have magnesium levels in the 10 to 16% range.  The higher your levels are above this, the greater the risk of yield loss.  Gypsum can improve yields even in the 10 to 16% range if your soils have a CEC above 20 since these soils will have greater than 35% clay content and will likely be colder and wetter soils with less aggregation.  The gypsum requirement may be less depending upon how high the CEC is.  Soils may also respond to the sulfur in gypsum if sulfur tests show low.

 

 

 

 

Share this entry
  • Share on Facebook
  • Share on X
  • Share on WhatsApp
  • Share on Pinterest
  • Share on LinkedIn
  • Share on Tumblr
  • Share on Reddit
  • Share by Mail
https://soilsolutions.net/wp-content/uploads/2019/02/2.png 295 559 Andrea Meyer https://soilsolutions.net/wp-content/uploads/2019/07/logo.png Andrea Meyer2019-02-19 09:40:032019-02-19 09:40:03Yields Can be Affected by Relative Magnesium Levels
Printer Friendly Printer Friendly

Recent Posts

  • Why is Gypsum Critically Important When Tiling Saline Sodic Soils?
  • Protect Your Plants—Get a Great Start To a High Yield Finish
  • Merry Christmas!
  • What Caused my Yield Variations in 2020?
  • Procidic Gives Yield Responses In Corn Even When Disease Presence is Low
Mascotte
Soil Solutions, LLC

2120 Pearl Street|Onawa, IA 51040|Phone: 712-433-0000|Toll Free: 877-474-SOIL| Email: andrea@soilsolutions.net

© 2025 Soil Solutions, LLC.  All Rights Reserved. | Privacy Policy

Website by: Heartland Internet Solutions

Should You Consider Higher Corn Plant Populations?Know your water pH and hardness especially when using Procidic.
Scroll to top

This site uses cookies. By continuing to browse the site, you are agreeing to our use of cookies.

OKLearn More

Cookie and Privacy Settings



How we use cookies

We may request cookies to be set on your device. We use cookies to let us know when you visit our websites, how you interact with us, to enrich your user experience, and to customize your relationship with our website.

Click on the different category headings to find out more. You can also change some of your preferences. Note that blocking some types of cookies may impact your experience on our websites and the services we are able to offer.

Essential Website Cookies

These cookies are strictly necessary to provide you with services available through our website and to use some of its features.

Because these cookies are strictly necessary to deliver the website, refusing them will have impact how our site functions. You always can block or delete cookies by changing your browser settings and force blocking all cookies on this website. But this will always prompt you to accept/refuse cookies when revisiting our site.

We fully respect if you want to refuse cookies but to avoid asking you again and again kindly allow us to store a cookie for that. You are free to opt out any time or opt in for other cookies to get a better experience. If you refuse cookies we will remove all set cookies in our domain.

We provide you with a list of stored cookies on your computer in our domain so you can check what we stored. Due to security reasons we are not able to show or modify cookies from other domains. You can check these in your browser security settings.

Other external services

We also use different external services like Google Webfonts, Google Maps, and external Video providers. Since these providers may collect personal data like your IP address we allow you to block them here. Please be aware that this might heavily reduce the functionality and appearance of our site. Changes will take effect once you reload the page.

Google Webfont Settings:

Google Map Settings:

Google reCaptcha Settings:

Vimeo and Youtube video embeds:

Privacy Policy

You can read about our cookies and privacy settings in detail on our Privacy Policy Page.

Privacy Policy
Accept settingsHide notification only